SBR, 7.62x39, thoughts

[TheRealJQP]

I've had some thoughts about SBRs and "pistols" chambered in rifle calibers bouncing around my noggin for a while and I figured I'd post them and see what others think. (I think this belongs in this forum because it's about both "pistols" and SBRs.)

My starting point is that I've tentatively come to the conclusion that 7.62x39 seems to be the best caliber to build a short SBR or rifle-caliber "pistol" around. It's a ubiquitous round, and looks to stay that way; it's affordable; and the ballistics seem much better suited to the role than 5.56. I hear good things about x39 ballistics even fired from super-short barrels.

To make a long story short, I think that on paper the Sig 556R or 556xi in 7.62x39, or whatever you call it seems like the ideal approach. It's modular like an AR, takes a proper rail like an AR, accepts a folding stock like an AK, and is designed around the caliber like an AK. Trouble is, everything I read suggests that Sig has dropped the ball on implementing the design. (ETA: shortest barrel I've seen offered for the 556xi is 10 or 10.x, which also seems less than ideal)

Personally, I think that other than the poor implementation, Sig has shown the way forward. I own 2 ARs myself, but now that I've decided that my next rifle-caliber firearm is going to be an SBR or rifle-caliber pistol, I find the AR platform lacking in those two key areas: folding stocks and 7.62x39 capability. The obvious other choice is the AK platform, but the lack of modularity (shouldn't have to drill or otherwise permanently modify a receiver to add a folding stock) and problematic optic mounting options leave me cold.

It seems like the gigantic step up in price should be the only down side to going outside the AR/AK universe to find what I want, but instead I don't really find anything all that appealing. I hear bad things about Sig's offerings. The Galil ACE seems like an expensive way to get the AK's dust-cover rail issues.

I find myself wishing a reliable company would step up and fill this void, but this almost seems like something that should be tackled by something bigger than a single manufacturer; maybe an industry group composed of a group of companies that come together and design a standard and agree to support it.

Any thoughts? Please correct me where I have something wrong.

 

[Girodin]

(ETA: shortest barrel I've seen offered for the 556xi is 10 or 10.x, which also seems less than ideal)

How short of a barrel do you want? Having used both 7.5" barrels and 11.5" barrels for 7.62x39. The 11.5" is preferable IMHO. I find it preferable for two reasons. Velocity and muzzle flash/blast. The 11.5" doesn't have much velocity loss compared to a 16" gun and the trade off for the reduction in length and weight is a good trade IMHO. The 7.5" gun can still be useful but there is a notable velocity loss.

As far as muzzle flash, the 7.5" barrel is a fire breathing dragon. Even with an A1 style flash hider it produces blinding flash not only at night but at a relatively well lit indoor range. At night it was truly blinding. I wondered what a vortex hider would do on that little gun.

The 11.5" gun with the same A1 hider was not blinding when fired at night.

The 7.5 is really blasty. Even fired outdoors you can feel the concussion on your face with each shot.

Apart from that, what is you envisioned role for this gun. Whether I wanted a 5.56, 7.62x39, 300 Blk or even a 9mm SBR would really depend on what exactly I wanted to do with that gun and role it was supposed to fill.

 

[bikemutt]

I would not expend the energy to SBR anything in 7.62x39. I had an AK pistol for a while, it was simply horrible to shoot. A fire-belching inaccurate arm to say the best about it, may have been my specimen of course. The good news is anyone can discover for themselves what a short barrel 7.62x39 is all about for generally under $500, if it seems fine then great, proceed.

The two rounds I've found that do well for me in a SBR are 300 BLK and 5.7x28.

 

[ifit]

Czech Point USA has VZ 58 pistols in 7.5" and 11" lengths and supports them by providing accessories like rails/mounts/adapters etc.. unfortunately I'm unable to sbr. I have AKs in 7.5" and 11".. And are surprisingly accurate even compared to my 16" lengths. Here's my 7.5" vz58...I also have a AR15 mag adapter(czechpoint) to use 7.62x39 AR15 mags.

 

[Casefull]

A fire-belching inaccurate arm to say the best about it

My truck gun is a 10.5 inch ar in 7.62 39 and it is anything but inaccurate. It will shoot under 2moa with a scope attached. You do lose 300 fps but it is still a very potent firearm. I never notice the increased muzzle blast. I like the Russian round better in the short barrels than my 5.56 pistol.

 

[bikemutt]

My truck gun is a 10.5 inch ar in 7.62 39 and it is anything but inaccurate. It will shoot under 2moa with a scope attached. You do lose 300 fps but it is still a very potent firearm. I never notice the increased muzzle blast. I like the Russian round better in the short barrels than my 5.56 pistol.

may have been my specimen of course

I qualified my post.

 

[Girodin]

A fire-belching inaccurate arm to say the best about it, may have been my specimen of course.

Never noticed any real mechanical accuracy difference with the shorter guns. They are like 16" AKs I've shot. Typically the limiting factor is what the shooter can do from field positions and the cheap ammo people shoot (which the seems to be what the OP wants it for.) The lower velocity affects trajectories but if I was planning on doing much shooting beyond 200 yards or so I'd pick a different cartridge.

AK pistols are much more difficult to shoot well than an AK SBR IME. An 11.5" AK's only real accuracy disadvantage is a shorter sight radius but thats what RDSs are for anyways.

There are a lot of different makes of AK pistols though. IMHO some of them are likely to be better than others.

Another option is a PTR 32 pistol. It has its own idiosyncrasies and trade offs. That said it has folding and collapsing stock options and options to mount red dots.

 

[yugorpk]

Take another look at the 300 BLK. Bullet choices are over the place even in factory loaded ammo. Its a reloaders dream unlike 7.62X39 , its optimized for a SBR and at major retailers like Cabellas its always on the shelf. Works great with silencers and with the light/fast loads its a great deer cartridge. It uses AR mags and really only requires a barrel change to go from .223 to 300 BLK in an AR-15. Plus a single SBR lower can use multiple uppers unlike the AK where you are limited to one caliber without major surgery.

 

[Casefull]

My starting point is that I've tentatively come to the conclusion that 7.62x39 seems to be the best caliber to build a short SBR or rifle-caliber "pistol" around. It's a ubiquitous round, and looks to stay that way; it's affordable; and the ballistics seem much better suited to the role than 5.56. I hear good things about x39 ballistics even fired from super-short barrels

Do not let anyone talk you out of the 7.62 39. It is faster than the 300 blk that everyone seems to push. I reload for mine and use any 308 bullets I want. Lee's dies come with a .308 diameter sizer so it is not a problem and I honestly cannot see much if any accuracy drop off as the bullets still contact the lands. I also load the .310/11 rounds. With 7g of Trailboss or Unique you have an excellent subsonic suppressed round. Plus you can throw in the steel cased cheapo ammo whenever.

 

[TheRealJQP]

Thanks for all the replies, lots to go over.

I don't really know how to answer the question about what role I expect the gun to fill. "Super-small with lots of firepower," I guess?

The good news is anyone can discover for themselves what a short barrel 7.62x39 is all about for generally under $500, if it seems fine then great, proceed.

You know, that's a really good point.

You bring up .300, what are some good guns for that caliber if you substitute it for x39 in my original post?

cheap ammo people shoot (which the seems to be what the OP wants it for.)

Yes and no. I wouldn't mind shooting good ammo in it, but I'd like it to perform adequately with the cheap stuff, too.

The lower velocity affects trajectories but if I was planning on doing much shooting beyond 200 yards or so I'd pick a different cartridge.

I'm seeing it as for short range. Your suggestion of under 200 yards works for me.

Sorry if I missed any points on my first read-through, will read everything again.

 

[TheRealJQP]

I'm not really interested in AR for this role. I'll take AK over AR; AK does optics better than AR does folding stocks.

How short of a barrel do you want? Having used both 7.5" barrels and 11.5" barrels for 7.62x39.

I'm thinking more 7.5" than 11.5. I like the size of the mini-Draco. I have heard many times about the crazy muzzle flash you describe, and yes, it gives me pause. How much does it interfere with follow-up shooting, and SD useability in general? I want this to be a viable (if not ideal) SD gun. I don't mind the loss of velocity so much.

Ifit, VZ 58 pistol in 7.5 sounds interesting. PTR 32 as well. I'll have to go check them out, thanks.

 

[TheRealJQP]

VZ58 and PTR 32P both look extremely sexy. Anyone want to talk up the folding/retractable stock options? I'm searching now but help would not go amiss.

ETA: this one billed as compatible with the PTR-32, goes in with no smithing:

http://whatacountry.com/hand-k-g3-a3-style-collapsible-stock.aspx

 

[yugorpk]

Do not let anyone talk you out of the 7.62 39. It is faster than the 300 blk that everyone seems to push. I reload for mine and use any 308 bullets I want. Lee's dies come with a .308 diameter sizer so it is not a problem and I honestly cannot see much if any accuracy drop off as the bullets still contact the lands. I also load the .310/11 rounds. With 7g of Trailboss or Unique you have an excellent subsonic suppressed round. Plus you can throw in the steel cased cheapo ammo whenever.

The discussion here is about SBR's. You'll get 2100 FPS out of an 8.5" barrel 300 BO shooting 110 grain Nossler Varmageddon. You won't get that out of factory 7.62X39 in a 10 inch barrel. Energy will be approximately the same in SBR's.

 

[Casefull]

You won't get that out of factory 7.62X39 in a 10 inch barrel. Energy will be approximately the same in SBR's.

I am not sure where you get your info sir. My info comes from my own research and testing. My 10.5 ar in 7.62 39 chronos 2100 fps with a 123g steel cased factory ammo. It also does 2100 fps, 123g bullet, 1680 powder, handloads. It beats the 300. You can see that for yourself if you check a reloading chart.

SBR with or without a shoulder stock has nothing to do with velocity.

 

[kimberkid]

I like the 7.62x39 SBR's ... top is a PTR-91 I bought as a receiver kit to build an HK-52 but the Atlantic HK32 pistols are the same thing ... the bottom is a SiG P556xi Russian

I like them both for different reason but it mostly boils down to I've got a registered HK sear, so the HK has the "happy switch" ... it's heavy and that comes in handy shooting F/A but if it weren't, I wouldn't like it nearly as much.

I've SBR'd an early 556 pistol(in 223) as well as the 556xi Russian. I really like the SiG in 7.62x39 and for me these short comings you speak of are non-issues. I wouldn't want any shorter of a barrel as the powder is wasted in a shorter barrel and would just be that much harder on a suppressor if you were to use one. IMHO, if your going to go shorter you may as well be shooting a pistol caliber or a 300AAC, Whisper, BlackOut or whatever you want to call it ... something made for shorter barrels.



I've also got an AMD-65 pistol I built myself ...



This is an old picture; It's currently got the new Magpul AK furniture, a permanently attached muzzle extension and 922r parts but I'm thinking I'm going back to the pistol config with it and move the stock over to another AK and get the new full length Magpul handguard.

 

[yugorpk]

I am not sure where you get your info sir. My info comes from my own research and testing. My 10.5 ar in 7.62 39 chronos 2100 fps with a 123g steel cased factory ammo. It also does 2100 fps, 123g bullet, 1680 powder, handloads. It beats the 300. You can see that for yourself if you check a reloading chart.

SBR with or without a shoulder stock has nothing to do with velocity.

And I can easily get 2050 FPS out of a 150 grain bullet from a 10 inch AR SBR with 17.2 grains H110 with no overpressure signs. The 2 cartridges are so close in ballistics its not even worth arguing about.

Ive owned quite a few 7.62X39 AR's over the years in addition to countless AK's. Their shortcomings are why I am advocating the 300 BLK in the AR especially in SBR's. .

 

[kimberkid]

And I can easily get 2050 FPS out of a 150 grain bullet from a 10 inch AR SBR with 17.2 grains H110 with no overpressure signs. The 2 cartridges are so close in ballistics its not even worth arguing about.

Ive owned quite a few 7.62X39 AR's over the years in addition to countless AK's. Their shortcomings are why I am advocating the 300 BLK in the AR especially in SBR's. .

You're right about the ballistics being so close it's not worth arguing over, but the benefit of the 7.62x39 over the 300 is ammo cost ... and not everyone likes to reload.

I have a couple AR's in 300 in both 16" and an 8.5" and I do load for it but I don't load anything but subsonics for it because have the 7.62x39

If I had only 1 it would be the x39 for the simple reason you can get ammo anywhere for it

 

[Olympus]

The big thing for me to consider when weighing 762x39 vs 300blk is the cost : time ratio. Steel cased 762x39 is like $0.22 to $0.23/round. You can buy it by the case and have a couple thousand rounds stocked up with just a few minutes of your time. You certainly can't come near that cost with commercial 300blk ammo. So that leaves you with reloading. If you're not alrealdy a reloader, that puts you way in the hole for cost on equipment and components. If you are a reloader, you can probably match the price of steel cased 762 ammo, but you have to be able to devote hours into case prep and reloading for that same several thousand rounds.

Right now, I just don't have the time to invest in bulk rifle reloading so it's an easy decision for me. 7.62x39

 

[TIMC]

I'm currently working on my second SBR, just waiting on the stamp to come. This one will be a short AK in 7.62x39 with a 10" barrel; as a pistol it shoots very well for what it is.

Not mine but this is the look I am going for with the AK SBR project I am working on.


My first SBR is an AR platform in .300 Blackout; IMHO it is the best platform and caliber to SBR. This little rifle is very accurate at 100 yards and a pleasure to shoot suppressed.

This is my AR SBR...

 

[TheRealJQP]

Right now I like the PTR-32P over the VZ58 pistol. Anyone want to suggest a third candidate? Also interested in whatever sources there are for the PTR; is Atlantic Firearms the only distributor for new PTRs, or are there other vendors?

 

[TIMC]

The Zavasta PAP M92 is a nice pistol that is easy to convert. They are also very easy to take down and clean.

 

[kimberkid]

I agree about the Zastava PAP (I've got an M85) but the drawback to it is the muzzel thread ... They've got that big ass 26x1.5 L thread. You're really limited on your muzzel devices ... I'd like to shoot mine suppressed but I don't think they make a phantom mount for it and I'm not interested enough to go out and buy a suppressor just for it.



Edited to correct thread pitch!

 

[TIMC]

There are adapters available, this is mine with the Thunderbeast 30P1 suppressor that has 5/8x24 threads.

 

[Girodin]

I'm thinking more 7.5" than 11.5. I like the size of the mini-Draco. I have heard many times about the crazy muzzle flash you describe, and yes, it gives me pause. How much does it interfere with follow-up shooting, and SD useability in general? I want this to be a viable (if not ideal) SD gun. I don't mind the loss of velocity so much.

Having used both, I'd pick the regular draco over the mini for what you are describing. I wouldn't even have to stop and think about it. The regular sized draco has more and arguably better options for mounting a RDS too IMHO. The mini is the choice if you want an AK that is as small as possible at the expense of just about everything else, without being absurdly impractical.

I don't really know how to answer the question about what role I expect the gun to fill. "Super-small with lots of firepower," I guess?

Are you interested in shooting suppressed?

What is the maximum range you foresee using the gun at?

What is the range you foresee using it at most often?

Is this something that realistically being able to shoot lots of cheap ammo on the range out weighs most other considerations? (i.e. 7.62x39 or 9x19 really is better than .300 BLK, 6.8, etc)

Are you heavily invested in anyone type of weapon or caliber (could be in terms of training time, mags, ammo stock, gear, etc).

How much would you like to spend?

How much are you willing to spend?

One other new and largely unproven option might be a sig MCX. Personally the MCX is on my wait and see list.

IMHO whether to get a 10-11.5" 5.56 AR(or similar), an AK SBR, a 9-10.5" 300 Blk, a 9x19 SBR, or even something out there like a PS90 SBR really depends on what you are realistically going to do with it and what set of trade offs best fits that. That's one reason some people own more than one or maybe even all of the above. Having been down this road (and in looking for other guns) there is no one true sword.

It can be a little tougher with SRBs but try and get some time handling (if not shooting) some of the options. I've guns that were wonderful on paper be a whole different story when I actually got trigger time.

One option is a PDW stock on the AR platform. It gets you almost as small as a folder (although the top gun appears to have a 7.5" barrel where as the bottom is a 10"). A 9" 300 BLK with a PDW stock would be

View attachment 737014

Also depending on why you want a folder, a LAW folding mechanism is an option (albeit like the PDW stock an expensive one.)

 

[TheRealJQP]

Are you interested in shooting suppressed?

Sure, but only if I can take the suppressor on and off quickly. I don't really know much about the subject, especially on HK platform, which I also know little about.

What is the maximum range you foresee using the gun at?

200 yds and under is good enough for me. I don't see it as a substitute for a true assault rifle or carbine.

What is the range you foresee using it at most often?

100 yards and under?

Is this something that realistically being able to shoot lots of cheap ammo on the range out weighs most other considerations? (i.e. 7.62x39 or 9x19 really is better than .300 BLK, 6.8, etc)

No, but again, having cheap ammo available is nice. Also, I will probably end up buying at least one AK at some point, and .300 and the rest wouldn't be useful in that case.

Are you heavily invested in anyone type of weapon or caliber (could be in terms of training time, mags, ammo stock, gear, etc).

No, but my plan is to keep the calibers to a minumum. I never planned on buying x39 until I realized it's a better SBR round than 5.56, and that I wanted a short, folding stock SBR.

How much would you like to spend?

Less is better, but I've been eyeballing the PTR-32P, and think the $950 price tag (plus the significant extra outlay for collapsible HK stock, improved charging handle, etc.) is worth it, if that's any indication.

How much are you willing to spend?

I think what the PTR-32P is going to cost me is probably my ceiling. I'd need to see considerable improvement over (what I'm reading about) that to want to pay more. It hits most of the features I want (could be lighter and smaller in OAL), and I've always loved the looks of HK weapons.

I'll have to take some time and check out the stocks you mention, thanks.